The 27oz bottle is larger and much better for longer trips without having to refill. This sport bottle is made from strong and durable plastic that will last for many years with repeated use. This filter will also treat up to 80 gallons of drinking water, approximately 3 months of use under normal conditions. It removes chlorine, bad taste and odor, as well as significant proportions of heavy metals, including Lead, Mercury, and Copper. It works great in standard bicycle racks and car holders. Simply fill bottle with water and drink. Bottle will filter the water as you drink!!